Use generic enable_backend method

Author: leolost2605

lib/Gestures/GestureController.vala

@@ -87,9 +87,7 @@ public class Gala.GestureController : Object {
 
     public bool recognizing { get; private set; }
 
-    private ToucheggBackend? touchegg_backend;
-    private TouchpadBackend? touchpad_backend;
-    private ScrollBackend? scroll_backend;
+    private Gee.List<GestureBackend> backends;
 
     private GestureBackend? recognizing_backend;
     private double gesture_progress;
@@ -105,6 +103,10 @@ public class Gala.GestureController : Object {
         Object (action: action, wm: wm, group: group);
     }
 
+    construct {
+        backends = new Gee.ArrayList<GestureBackend> ();
+    }
+
     /**
      * Do not call this directly, use {@link RooTarget.add_controller} instead.
      */
@@ -120,26 +122,22 @@ public class Gala.GestureController : Object {
 
     public void enable_touchpad (Clutter.Actor actor) {
         if (Meta.Util.is_wayland_compositor ()) {
-            touchpad_backend = new TouchpadBackend (actor, group);
-            touchpad_backend.on_gesture_detected.connect (gesture_detected);
-            touchpad_backend.on_begin.connect (gesture_begin);
-            touchpad_backend.on_update.connect (gesture_update);
-            touchpad_backend.on_end.connect (gesture_end);
+            enable_backend (new TouchpadBackend (actor, group));
         }
 
-        touchegg_backend = ToucheggBackend.get_default (); // Will automatically filter events on wayland
-        touchegg_backend.on_gesture_detected.connect (gesture_detected);
-        touchegg_backend.on_begin.connect (gesture_begin);
-        touchegg_backend.on_update.connect (gesture_update);
-        touchegg_backend.on_end.connect (gesture_end);
+        enable_backend (ToucheggBackend.get_default ()); // Will automatically filter events on wayland
     }
 
     public void enable_scroll (Clutter.Actor actor, Clutter.Orientation orientation) {
-        scroll_backend = new ScrollBackend (actor, orientation, new GestureSettings ());
-        scroll_backend.on_gesture_detected.connect (gesture_detected);
-        scroll_backend.on_begin.connect (gesture_begin);
-        scroll_backend.on_update.connect (gesture_update);
-        scroll_backend.on_end.connect (gesture_end);
+        enable_backend (new ScrollBackend (actor, orientation, new GestureSettings ()));
+    }
+
+    internal void enable_backend (GestureBackend backend) {
+        backend.on_gesture_detected.connect (gesture_detected);
+        backend.on_begin.connect (gesture_begin);
+        backend.on_update.connect (gesture_update);
+        backend.on_end.connect (gesture_end);
+        backends.add (backend);
     }
 
     private void prepare () {